// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)

#undef _GNU_SOURCE
#include <stdio.h>
#include <string.h>

#include "libbpf.h"
#include "libbpf_internal.h"

/* make sure libbpf doesn't use kernel-only integer typedefs */
#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64

#define ERRNO_OFFSET(e) ((e)-__LIBBPF_ERRNO__START)
#define ERRCODE_OFFSET(c) ERRNO_OFFSET(LIBBPF_ERRNO__##c)
#define NR_ERRNO (__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START)

static const char *libbpf_strerror_table[NR_ERRNO] = {
    [ERRCODE_OFFSET(LIBELF)] = "Something wrong in libelf",
    [ERRCODE_OFFSET(FORMAT)] = "BPF object format invalid",
    [ERRCODE_OFFSET(KVERSION)] = "'version' section incorrect or lost",
    [ERRCODE_OFFSET(ENDIAN)] = "Endian mismatch",
    [ERRCODE_OFFSET(INTERNAL)] = "Internal error in libbpf",
    [ERRCODE_OFFSET(RELOC)] = "Relocation failed",
    [ERRCODE_OFFSET(VERIFY)] = "Kernel verifier blocks program loading",
    [ERRCODE_OFFSET(PROG2BIG)] = "Program too big",
    [ERRCODE_OFFSET(KVER)] = "Incorrect kernel version",
    [ERRCODE_OFFSET(PROGTYPE)] = "Kernel doesn't support this program type",
    [ERRCODE_OFFSET(WRNGPID)] = "Wrong pid in netlink message",
    [ERRCODE_OFFSET(INVSEQ)] = "Invalid netlink sequence",
    [ERRCODE_OFFSET(NLPARSE)] = "Incorrect netlink message parsing",
};

int libbpf_strerror(int err, char *buf, size_t size)
{
    int ret;

    if (!buf || !size)
        return libbpf_err(-EINVAL);

    err = err > 0 ? err : -err;

    if (err < __LIBBPF_ERRNO__START)
    {
        ret = strerror_r(err, buf, size);
        buf[size - 1] = '\0';
        return libbpf_err_errno(ret);
    }

    if (err < __LIBBPF_ERRNO__END)
    {
        const char *msg;

        msg = libbpf_strerror_table[ERRNO_OFFSET(err)];
        ret = snprintf(buf, size, "%s", msg);
        buf[size - 1] = '\0';
        if (ret >= size)
            return libbpf_err(-ERANGE);
        return 0;
    }

    ret = snprintf(buf, size, "Unknown libbpf error %d", err);
    buf[size - 1] = '\0';
    if (ret >= size)
        return libbpf_err(-ERANGE);
    return libbpf_err(-ENOENT);
}
